Motor vehicles, such as cars, trucks, SUVs, CUVs, and vans, for example, include restraints in the form of various types and styles of seatbelts, which are intended to be worn by an occupant of each of the seats of the vehicle. In general seatbelts are designed to help secure the occupant in position within a respective seat in the event of an accident or other abrupt movement of the vehicle. Many seatbelts require manual buckling by the occupant to function. In other words, it is up to the occupants of the seats of the vehicle to wear their seatbelts in order for the seatbelt to be effective for its intended purpose.
Many motor vehicles with seatbelts further include various systems or devices to monitor for and encourage use of seatbelts by occupants of the vehicle. Most prior forms of such monitoring systems include a switch or other sensor coupled with the seatbelt buckle that functions by telling the system whether or not the buckle insert is received within the buckle receptacle. An audible tone and/or a visible indication may be presented as long as the seatbelt remains unbuckled. Some prior systems further communicate with a weight sensor within the seats to allow the system to present such warnings only in the instance where an unbuckled seatbelt is associated with an occupied seat. However, such monitoring systems can be defeated by an occupant buckling the seatbelt prior to entering the vehicle and sitting on top of the buckled seatbelt.
Other monitoring systems have added the ability to monitor additional features of the seatbelt by additional means, including requiring that the seatbelt be withdrawn by a minimum threshold amount to disable indication messages or ignition/gear selector interlocks. However, such systems can still be defeated by drawing out an amount of an unused but buckled seatbelt or by other means. Accordingly further advances in seatbelt use monitoring systems are desired.